Jamieson, Fausset and Brown on 2 Kings 1:9

9. Then the king sent unto him a captain of fifty--Any appearance of cruelty that there is in the fate of the two captains and their men will be removed, on a full consideration of the circumstances. God being the King of Israel, Ahaziah was bound to govern the kingdom according to the divine law; to apprehend the Lord's prophet, for discharging a commanded duty, was that of an impious and notorious rebel. The captains abetted the king in his rebellion; and they exceeded their military duty by contemptuous insults.

man of God--In using this term, they either spoke derisively, believing him to be no true prophet; or, if they regarded him as a true prophet, the summons to him to surrender himself bound to the king was a still more flagrant insult; the language of the second captain being worse than that of the first.